Sheng ji

Sheng ji is a family of point-based, trick-taking card games played in China and in Chinese immigrant communities. They have a dynamic trump, i.e., which cards are trump changes every round. As these games are played over a wide area with no standardization, rules vary widely from region to region.
The game is most commonly played with two decks of cards, which can be called bāshí fēn, tuō lā jī, shuāng kōu, or shuāng shēng ; another variant is called zhǎo péngyǒu, which has five or more players and two or more decks. Alternatively, it can be played with one deck, in which case the game may be called dǎ bǎi fēn or sìshí fēn.
The article below mainly describes the bashi fen variant, with players playing with two decks and in fixed partnerships.

Players and objective

The game is played with four players in fixed partnerships, with players sitting across each other forming a team. Each team has a rank that they are currently playing, henceforth referred to as their score. At the beginning of a match, both teams start at a score of 2.
One team is designated the "declarers" and the other team is designated the "opponents". This designation of teams is determined in the process of the game and will change frequently.
The objective and scoring for each team is slightly different:

If the "declarers" prevent the "opponents" from taking 80 points in tricks during a round, the "declarers" score is incremented by one, and the declarers remain as the declarers.
If the "opponents" take 80 points in tricks during a round, the "opponents" score is not incremented, but the opponents become the declarers for the next round and have the chance to increment their score. However, in some variations, if the opponents exceed 80 points in tricks, their score is incremented according to various thresholds.

Ultimately, the final objective of the game is to raise the team's score above ace, while preventing the other team from doing so. When a team passes a score of ace, a match usually ends with their victory. This may take several hours, so shorter games may end at a lower threshold, or begin with players' scores higher than two. If an even longer game is desired, players can wrap back around to 2 after passing ace.

The deck

The game is played with two French-suited standard decks, including two jokers per deck, giving a total of four jokers and 108 cards overall. In general, there is one deck for every two players, so for example, a six-player game would use three decks, giving six jokers and 162 cards in total.
The jokers are separated into red and black. Because there are no standards for jokers, some card decks include two identical jokers, which then have to be marked as "big" and "small".
The order of the cards depends on the dominant suit and rank, which are determined before every round. The typical order, from highest to lowest, is:

Red jokers
Black jokers
Cards in both the dominant suit and rank
Other cards in the dominant rank, equally ranked
Other cards in the dominant suit, following the descending order ace through 2
Cards in other suits, following the descending order ace through 2

where the first five categories are all considered to be part of the trump suit. It is possible to play with only a dominant rank without a dominant suit. In that case, the first four categories are all considered to be part of a fifth suit, while the other four suits all fall into the sixth category.
If two or more equally ranked cards or combinations are played during a trick, the first one played wins.
For example, in a certain round, if the seven of clubs is dominant, then the order of the cards is:

Red jokers
Black jokers
Seven of any other suit
Cards in other suits, following the order ace, king, queen, etc., down to 2.

Note that the other sevens are no longer considered members of their respective suit, but are now considered part of the trump suit; moving the other sevens to the trump suit means the rank 8 and 6 cards are adjacent for all suits. The trump suit consists of the red jokers, which are equally ranked with each other, followed by the black jokers, sevens of clubs, sevens of other suits, and the remainder of the trump suit, ordered from A to 2.
If play proceeds without a declared suit as trump, a fifth suit is created consisting of the jokers and the dominant rank cards. Each of the dominant rank cards is equal. For example, consider the case where the dominant rank is 7 and there is no declared dominant suit:

Point cards

In the deck, only kings, 10s, and 5s are worth points when taken as a trick. All kings and 10s are worth 10 points each, while 5s are worth 5 points each, although the presence of the points do not affect the order of the cards. In two decks, there are a total of 200 points:

8 kings = 80 points
8 10s = 80 points
8 5s = 40 points

All other cards do not award points.
Because the winning criteria for the round depends only on the number of points scored by the opponents:

The declarers do not need to keep track of the points scored by the tricks the declarers have taken, and may set aside the cards after the trick is taken.
The opponents only need to keep track of the point cards in the tricks the opponents have taken, and may set aside non-point cards after the trick is taken.
Dealing

The cards are dealt to each player in Chinese fashion, where the players take turns drawing one card at a time in counter-clockwise order. The deal is initiated in one of two ways:

One player shuffles the cards and lets any other player cut, then draws the first card.
One player shuffles the cards, then turns over one of them. That player then counts off the number of positions equivalent to the face-up card going counter-clockwise, starting from their own seat, where aces count as one, jacks as 11, queens as 12, and kings as 13. If the card turned over is a joker, another card must be turned over. The player whose position is indicated after the count draws the first card after the player to their left cuts.

Drawing continues until everyone has drawn 25 cards, leaving a pool of 8 reserve cards, also known as the bottom , which will be examined by the dealer prior to the start of play. During the initial drawing of the cards, the dominant suit is determined by bidding.

Determining the dominant suit and rank

The dominant rank is always equal to the score of the declarers in any particular round. Since both teams start with a score of 2, the dominant rank in the first round is 2. When the declarers obtain a score of 5, the rank for that round is 5; when the score of the declarers is raised to 7, the rank is 7, and so on.

Bid	Player	Dominant suit	Notes
	N		North leads bidding with, making hearts the dominant suit.
	E		East overrides North's original bid with an identical pair of, making clubs the dominant suit.
	N		North reinforces original bid with another, forming a pair and reinstating hearts as the dominant suit. This should do before East override it.
black joker, black joker	S	No-trump	South wins bid with a pair of black jokers; jokers trump all suits.

The dominant suit, on the other hand, is determined during the drawing of cards: any player may bid a suit by revealing a card in the dominant rank; the suit of that card becomes the dominant suit. For example, if the rank is 7, a player may reveal a, resulting in hearts becoming the dominant suit.
If other player do not agree to the dominant suit set, they may override the bid by revealing doubles of another suit in the same rank to cancel the original bid, making the doubled suit the dominant suit. For example, consider a round where the dominant rank is 9. Player North reveals a to make hearts dominant, but Player East then reveals a pair of, overriding North's initial bid and making clubs the dominant suit. In order to prevent this, North may bid another, making a pair which takes precedence over East's override bid and secures the declaration of hearts as the dominant suit.
Any new override bids must exceed prior bids. Players are not allowed to reinforce their partner's bid. In some variations, one or more joker cards may be included in a bid, allowing three or more cards in a bid. A player who has already made a bid for the trump suit may only "reinforce" their bid by adding card to their original bid.
In some variations, players may bid two identical jokers to declare no-trump rounds, where there is no dominant suit and the trump suit will only consist of the jokers and the eight cards of the trump rank. A single joker is not allowed as a valid no-trump bid.
In other cases, where no bids are made to determine the dominant suit, then the first card in the kitty is turned over, and its suit is adopted as the dominant suit. If the card turned over is a joker, there are three potential actions:

turn over the subsequent card
play no-trumps round
reshuffle the cards

In other variations, the cards in the kitty are continuously turned over until the trump rank appears, in which that suit is the trump and no more cards are flipped. If no cards of the trump rank appear, the biggest card's suit is trump, or if two cards are tied for biggest, then the one flipped first is declared the trump suit.

Determining declarers and dealers

The next action is taken by the dealer, also known as the leader of the declarers. The dealer starts every round, and plays an important role in helping their team increase their rank in that round.

In the first round, the dealer can be determined during the draw:
* The first player to reveal any rank 2 card from the cards they drew will instantly become the dealer, and that player's team becomes the declarers while the other team becomes the opponents.
* The first player to reveal a pair of identical rank 2 cards will become the dealer, as a variation
* The first player to reveal a pair of identical joker cards will become the dealer, as a variation
In subsequent rounds, if the declarers have defended their points in the previous round, they will remain as declarers, but the partner of the previous dealer will become the new dealer. If the opponents have taken 80 points in tricks, they will become the new declarers, with the player sitting on the right of the previous dealer becoming the new dealer.